The invention relates to a vacuum cleaner particularly, but not exclusively, to a robotic vacuum cleaner.
Vacuum cleaners operable in more than one mode, i.e., in upright mode and in cylinder mode, are well known. In the upright mode, the cleaner operates by drawing dirty air into the cleaner by way of a cleaner head which travels across the floor or other surface to be cleaned. In the cylinder mode, the dirty air is drawn into the cleaner via a hose or a hose and wand assembly. Most cleaners which are convertible between the two modes of operation are essentially upright cleaners which have permanently attached hoses which can be brought into operation when cylinder cleaning is required. In some cases, the hose is permanently connected to the inlet of the dirt and dust separating apparatus of the cleaner and the distal end of the hose is then stored in a hollow socket during upright cleaning so that the hose becomes part of the dirty air inlet path during upright cleaning. Such an arrangement results in losses which are higher than is desirable during upright cleaning due to the passage of the air through a hose rather than through a smooth conduit or pipe. In other arrangements, the hose is permanently connected to the main body of the cleaner but a valve is used to select whether dirty air is drawn into the cleaner through the cleaner head or through the hose. The operation of the valve can be made dependent upon the angle of inclination of the main body of the upright cleaner as illustrated and described in EP 0 134 654 B. This type of arrangement is better than the aforementioned alternative arrangement during upright cleaning because the dirty air is not required to pass through a hose. However, in such an arrangement, the airflow passage is often longer than is desirable during cylinder cleaning and, as a result, avoidable losses can occur.
Autonomous or robotic vacuum cleaners have also been proposed. Robotic vacuum cleaners operate in a manner which is different to that of both upright and cylinder cleaners. In the normal or autonomous mode of operation, the cleaner traverses the surface to be cleaned under its own power and using its own navigation system so that human intervention is not required. Dirty air is drawn into the machine through a cleaner head in a manner similar to that used in upright cleaning using an upright cleaner. Robotic vacuum cleaners are shown and described in, inter alia, U.S. Pat. No. 5,781,960 and U.S. Pat. No. 5,109,566. The latter of these documents also indicates that a hose can be attached to the robotic vacuum cleaner for the purpose of attaching a conventional suction hose for manual cleaning of areas which cannot be reached by the robotic cleaner. As in conventional vacuum cleaners, a device for changing the air path so as to select the dirty air inlet for the desired mode of operation is included. Such changeover devices are inevitably prone to failure on occasion and normally cause a discontinuity in the airflow paths in which they are placed. This can lead to frictional losses and/or pressure drops within the relevant cleaner.
It is an object of the present invention to provide a vacuum cleaner which is convertible between two different modes of operation easily and conveniently. It is a further object of the present invention to provide a vacuum cleaner which is convertible between two different modes of operation in a manner which avoids unnecessary losses or in which unnecessary losses are minimised.
An aspect of the invention provides a vacuum cleaner comprising a chassis for releasably supporting a dirt and dust separating apparatus for separating dirt and dust from an airflow, and a cleaner head having an outlet communicating releasably with an inlet of the dirt and dust separating apparatus, the dirt and dust separating apparatus being releasable from the chassis to allow the dirt and dust separating apparatus, or a part thereof incorporating the inlet to move into an alternative position in which the outlet of the cleaner head is not in communication with the inlet of the dirt and dust separating apparatus and in which an alternative dirty air inlet may be connected to the inlet of the dirt and dust separating apparatus.
This arrangement allows a hose, or a hose and wand assembly, to be attached directly to the inlet to the dirt and dust separating apparatus without forcing the incoming air which then enters via the hose to travel through the ducting designed to carry dirty air from the cleaner head. When the cleaner head is in use, the incoming air is not forced to travel through the hose or any other ducting designed to carry air from the hose. In each case, the airflow path is kept to an absolute minimum. Furthermore, there is no changeover valve involved which us the risk of malfunction or failure in this area and also avoids the need for the incoming air to pass through a discontinuity in the airflow path of the cleaner.
In a preferred embodiment, the dirt and dust separating apparatus comprises, or is surrounded by, a rigid shell or housing. This makes the movement of the apparatus, or the relevant part thereof, easier and more manageable for the user. More preferably, the dirt and dust separating apparatus is generally cylindrical, with one end portion being attachable to a main body in more than one position relative thereto, advantageously in two diametrically opposed positions. The diametric opposition of the two said positions is advantageous because the risk of the wrong position being inadvertently selected by the user is minimised. Other spacings of the two said positions are possible, a spacing of 90xc2x0 being advantageous as well. As an alternative to removing the part of the separating apparatus incorporating the inlet and reattaching it in a new position, the part of the separating apparatus incorporating the inlet can be rotatable with respect to the remainder of the separating apparatus. Suitable indicia or physical formations can be used to mark the positions between which the part of the separating apparatus incorporating the inlet should be rotated
It is preferred that the dirt and dust separating apparatus comprises a centrifugal separator, more preferably two cyclones arranged in series. Such an arrangement provides efficient and effective separation of dirt and dust from the airflow.
Preferably the vacuum cleaner comprises means for sensing the position of the dirt and dust separating apparatus, or the part incorporating the inlet, and for controlling operation of the cleaner according to the sensed position. When the cleaner is an autonomous cleaner which is capable of autonomously moving across an area, the sensed position of the inlet can control whether the cleaner operates in an autonomous mode or a manual mode.
Preferably, when the sensing means senses that the outlet of the cleaner head is not in communication with the inlet of the dirt and dust separating apparatus, operation of the brush bar of the cleaner is inhibited.